Pulse generation system

ABSTRACT

A pulse generation system employing a storage device excited by energy from an alternating current power source. The energy stored in the storage device is coupled through a variable mutual coupling network to a load. By varying the mutual coupling with time, the shape of the transferred energy is controlled.

0 United States Patent 1 3,568,064

[72] Inventor Paul R-Johannessen [56] References Cited 7 g g Lex'ngmn Mass UNITED STATES PATENTS [21] Appl. No. 770,292 [22] Filed Oct 24, 1968 1,462,038 7/1923 Hartley 325/173X [45] Patented Mar. 2, 1971 2, 53,634 9/1958 Deise 307/106 Assignee Sylvilllia Electric Products, Inc. Primary Examiner--Robert L. Richardson Attorneys- Norman J. O'Malley, Elmer J. Nealon and David M. K 54 PULSE GENERATION SYSTEM 8 Claims, 3 Drawing Figs.

[52] US. Cl 325/173, ABSTRACT: A pulse generation system employing a storage 325/105, 325/ 141, 325/ 161 device excited by energy from an alternating current power [51] Int. Cl 1104111/02 source. The energy stored in the storage device is coupled [50] Field of Search 307/252, through a variable mutual coupling network to a load. By 260, 305; 325/105, 141, 161, 162, 164, 173; varying the mutual coupling with time, the shape of the trans 333/24 ferred energy is controlled.

. STORAGE ANTENNA /l4 l6) DEVICE I 12 r E "I r' 1 l c2 VARIABLE I Ac L MUTUAL L, c, POWER 2 I I QOUPLING I I Sou ROE I l CIRCUIT I I CONTROL CIRCUIT PATENTEI) m 219?: 3; 568.064

sum 1 or 2 AGENT PATENTEDHAR 2m: 3;568,0s4

MHZ-0P2 FROM FROM CONTROL TO STORAGE CRT ANTENNA DEVICE BIAS SUPPLY IN VENTOR PAUL R. JOHANNESSEN BY 3W mm AGENT PULSE GENERATION SYSTEM BACKGROUND OF THE INVENTION This invention relates to pulse generation systems and in particular to high power radio frequency systems of the pulse modulation type.

Conventional pulse generation systems useful, for example, in radio frequency systems employ high power vacuum tubes or solid state power amplifiers to provide the RF power and to shape the envelope of the RF pulse. In such a system the RF power source (the power amplifier) must be rated for the peak pulse power, while the average RF power may be several orders of magnitude less the peak RF power. It would be advantageous to have pulse generation system in which the RF source need only supply the average power. It is, therefore, one object of this invention to permit the generation of high power RF pulses with the use of a low power RF power source.

BRIEF SUMMARY OF THE INVENTION A high power pulse generation system according to the present invention employs an alternating current storage device, such as a high-Q inductance and capacitance circuit. The storage device is connected to a load, such as a radio frequency antenna, through a variable mutual coupling network. A control circuit, also connected to the variable mutual coupling network, supplies a control signal that varies with time. In response to the control signal, the mutual coupling between the storage device and the antenna is varied with time to allow the energy stored in the storage device to be unilaterally transferred to the antenna. By varying the mutual coupling with time, it is possible to shape the envelope of the transferred energy and thereby shape the radio frequency pulse envelope.

DESCRIPTION OF THE DRAWINGS The construction and operation of the invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a block diagram of a pulse generation system according to the present invention;

FIG. 2 is a schematic representation of a variable mutual coupling network employed in the embodiment shown in FIG. 1; and

FIG. 3 is a schematic representation of a control circuit employed in the embodiment shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION A block diagram of a pulse-transmitting system according to the present invention is shown in FIG. 1. The system includes an alternating current source 10, such as a radio frequency generator, connected to a storage device 12, such as a high-Q dummy antenna. The storage device 12 is connected to a radio frequency load such as an antenna 14 through a variable mutual coupling circuit 16 to be discussed in detail hereinafter. Also connected to the variable mutual coupling circuit 16 is a control circuit 18.

In operation, the storage device 12, the electrical equivalent of which is represented by a high-Q series-connected inductor L and capacitor C is excited by an alternating current voltage V(t) from the AC power source 10. In the absence of mutual coupling in the mutual coupling circuit 16, the storage device 12 is electrically isolated from the antenna 14. When mutual coupling is introduced by the variable mutual coupling network 16, in response to a control signal from the control circuit 18, energy is transferred from the storage device 12 to the antenna 14. Antenna 14 is represented by its electrical equivalent, namely, the. series combination of an inductor L and capacitor C The wave-shape of the power transferred into the antenna 14 is set by change of mutual inductance with respect to time in the variable mutual coupling circuit 16. This change in mutual inductance with respect to time, dM/dt is in turn set by the current versus time waveform of the signal from the control circuit 18.

Assuming, for example, the mutual inductance, M, of the variable mutual coupling circuit 16 is constant, the two natural frequencies, :0 of the storage device 12 and the antenna 14 are equal (L L, L and C C C), and the Q's of both the storage device and the antenna circuits are high, the relationship between the natural frequency,

and the charging and discharging frequency, m between the storage device 12 and the antenna 14 can be expressed as follows:

w +wz *..,1-@2"L-M For example, if it is required to complete the transfer of energy from the storage device 12 to the antenna 14 within seven cycles of a kHz. carrier frequency from the alternating current source 10, to, would equal 6.98 X 10 /rad/sec, (0 would equal .209 X 10 /rad/sec and the ratio of M to L would be 1 to 15.

By varying the mutual coupling with time, it is possible to shape the envelope of the transferred energy and thereby shape the envelope of the radiated signal. A circuit, the mutual inductance of which can be varied, is shown in FIG. 2 and employs four nonlinear inductors L through L having essentially the same nonlinear characteristics. (A quadratic nonlinear B-I-I characteristic is preferred as this characteristic precludes the generation of odd harmonics of the RF frequency.)

Induction L includes four windings, two of which are RF windings 50a and 50b, one of which is a bias winding 50c and one of which is a control winding 50d. Likewise, L L and L, include corresponding windings 52a52d, 54a-54d, and 56a-56, respectively. The bias and control windings 50c and 50a of inductor L are connected in series opposing arrangements with the respective bias and control windings 52c and 52d of inductor L and two RF windings 50a and 50b of inductor L, are connected in series aiding arrangements with the respective RF windings 52a and 52b of inductor L Likewise, RF windings 54a and 54b are connected in series aiding arrangements with the respective RF windings 56a and 56b, and the bias and control windings 54c and 54d are connected in series opposing arrangements with respective windings 56c and 56d. By employing the bias and control windings in series opposing arrangements and the RF windings in series aiding for each pair of inductors L and L and L and L a control voltage applied across the series-connected control windings is not coupled to the two sets of series-connected RF windings. This lack of coupling isolates the RF windings from the bias and control windings.

The series combination of saturable inductors L and L is connected in series with the series combination of saturable inductors. L and L such that the series combination of control windings 50d and 52d is in series opposition with the series combination of control windings 54d and 56d. Similarly, the series combination of RF windings 50a and 52a are connected in series opposition with the series combination of RF windings 54a and 56a while the series combination of RF windings 50b and 52b is connected in a series aiding arrangement with the series combination of RF windings 54b and 56b. By connecting the combination of saturable inductors L and L in series with the combination of saturable inductors L and L as described hereinabove, electric isolation is obtained between the two series combination of four RF windings, namely, the series combination of windings 50a, 52a, 54a and 56a is electrically isolated from the series combination of windings 50b, 52b, 54b and 56b when all the saturable inductors have the same value of inductance.

Under balanced conditions (when the inductance values of the two series combination of four RF windings are equal), the energy stored in the RF storage device 12 will not be transferred into the antenna 14 because voltages induced across the RF windings 50a, 52a, 54a and 56a will not appear across the RF windings 50b, 52b, 54b, and 5612. When a control signal from the control circuit 18 is applied to the control windings, current flows through the series combination of control windings 50d, 52d, 54d and 56d which, in turn, causes an increase in the inductance of the series combination 50a and 52a and a decrease in the inductance of the series combination of windings 54a and 56a. This unbalance in inductance causes electric coupling to exist between the series combination of RF windings 50a, 52a, 54a and 56a that is connected to the storage device 12 and the series combination of RF windings 50b, 52b, 54b and 56b that is connected to the radiating antenna, whereby the energy stored in the storage device 12 and its associated RF windings is transferred to the antenna 14. As stated hereinabove, the shape of the energy waveform in the antenna 14 is determined by the shape of the current waveform of the control signal from the control circuit 18.

Bias winding 50c is connected in series opposition with bias winding 52c and similarly bias winding 54c is connected in series opposition with bias winding 560. The series combination of bias windings 50c and 52c is connected in turn in series aiding with the series combination of bias windings 54c and 560. A bias supply 50 is connected to the series combination of the bias windings. The resultant bias winding current sets the quiescent operating point of the inductors on their respective B-l-l (hysteresis) curves.

There are many embodiments of control circuits that may be employed with the pulse generation system of FIG. 1. For example, in a pulsed radar system, the control circuit could be a free-running current pulse generator having a current pulse of a fixed pulse width and a fixed repetition rate.

A second embodiment of a control circuit 18 useful, for example, in a system where a variable repetition rate and pulse polarity to 180 phase of the RF) are required, is shown in FIG. 3. A first silicon-controlled rectifier SCR, has its anode connected to the positive terminal of a low voltage power supply 40 and its cathode to the common junction of the anode of a second SCR, SCR and one end of an inductor L The cathode of SCR is connected to the negative terminal of a second low voltage power supply 42. The other end of inductor L is connected to a common junction formed by one end of a capacitor C the anode of a third SCR, SCR and the cathode of a fourth SCR, SCR,. The cathode of SCR and the anode of SCR, are connected together and to the other end of the capacitor C through a second inductor L The common junction of capacitor C and the inductor L is connected to the control winding in the mutual coupling circuit through the output terminals 44 of the control circuit.

To generate a positive control pulse at the output terminals 44, a trigger pulse from the trigger source 46 is applied to the gate electrode of SCR, allowing the current i to flow from the positive terminal of the first low voltage power supply 40 through the series combination of SCR,, inductor L capacitor C and the control windings of the mutual coupling network 16. To generate a negative control pulse at the terminals 44, a trigger pulse from the trigger source is directed to the control gate of SCR allowing the current i to flow from the negative terminal of the second low voltage power supply 42 through the series combination of SCR inductor L capacitor C and the control windings of the mutual coupling network 16. The combination of the capacitor C inductor L and the control windings of the variable mutual coupling circuit 16 forms a resonant circuit that determines the modulation rate of the RF pulse.

If two successive positive pulses are to be generated at the output terminals 44, the trigger source 46 directs a trigger pulse to SCR during the time interval between the successive pulses to discharge the capacitor C such that another positive pulse can be generated. Similarly, if two successive negative pulses are to be generated at the output terminals 44, the trigger source 46 directs a trigger pulse to SCR, to discharge the capacitor C;,.

It has been demonstrated that the use of an RF storage device and variable mutual coupling network, as described herein, can be employed to generate high power RF pulses.

lclaim:

l. A pulse generation system comprising:

an alternating current source including a radio frequency source;

storage means having an input terminal and an output terminal and being adapted to store alternating current energy from said alternating current source:

a load means including an antenna means;

a variable mutual coupling means having first and second input terminals and an output terminal, said first input terminal being connected to the output terminal of said storage means and said output terminal being connected to said load means; and

a control circuit having an output terminal connected to said second input terminal of said variable mutual coupling means, said control circuit being operative to supply a control signal of predetermined shape to said variable mutual coupling means, said variable mutual coupling means being operative in response to the control signal from said control circuit to introduce mutual coupling between the first and second input terminals of said variable mutual coupling means whereby the alternating current energy in said storage means is transferred to said load means, said variable mutual coupling circuit including four saturable inductors, each of said saturable inductors having first and second alternating current windings of equal inductance and a control winding, each of said saturable inductors being operative in response to a control signal on its control winding to change the value of inductance of said first and second alternating current windings, the first alternating current windings of said four saturable inductors being connected in series, the second alternating current windings of said four saturable inductors being connected in series and the control windings of said four saturable inductors being connected in series, the series-connected first and second alternating current windings being connected in an inductive balanced configuration with no mutual coupling between said series-connected first alternating current windings and said series-connected control windings, said seriesconnected first alternating current windings being connected to said storage means, said series-connected second alternating current windings being connected to said antenna means and said series-connected control windings being connected to said control circuit, said series-connected control windings being operative in response to a signal from said control circuit to change the inductance values of the series-connected first and second alternating current windings whereby an inductance unbalance is created between the series-connected first alternating current windings causing the energy stored in said storage means to be transferred to said antenna means.

2. A pulse generation system according to claim 1 wherein said variable mutual coupling circuit comprises:

six terminals;

a first saturable inductor having first and second alternating current windings and a control winding operable in response to a control signal to change the inductance value of said first and second alternating current windings, one end of said first alternating current winding being connected to the first terminal of said six terminals, one end of said second alternating current winding being connected to the second terminal of said six terminals, and one end of said control winding being connected to the third terminal of said six terminals;

a second saturable inductor having first and second alternating current windings and a control winding, operable in response to a control signal to change the inductance value of said first and second alternating current and the other end of the first alternating current winding of said fourth saturable inductor being connected in a series-opposing arrangement to the other end of the first winding of the second saturable inductor, one end of the second alternating current winding of said fourth saturable inductor being connected to the other end of the second alternating current windingof said third saturable inductor in a series aiding arrangement, and one end of the control winding of said fourth saturable inductor being connected in series opposition to the other end of the control winding of said third saturable inductor and the other end of the control winding of said fourth saturable inductor being connected in a series opposing arrangement to the other end of the control winding of said second'saturable inductor, thus the 'series combination of the first alternating current windings of said first and second saturable inductors are connected in series opposing arrangement with the series combination of the first alternating current windings of said third and fourth a control circuit output terminal;

a capacitor having first and second terminals, said second terminal being connected to said control circuit output terminal;

windings, one end of the first alternating current winding 5 a first silicon-controlled rectifier having its anode conof said second saturable inductor being connected in a senected to the positive output terminal of said supply ries aiding arrangement to the other end of the first altersource, its gate electrode connected to the first output nating current winding of said first saturable inductor, terminal of said trigger means and its cathode connected one end of said second alternating current winding of said to the first terminal of said capacitor, said first silicon second saturable inductor being connected in a series aid- 10 controlled rectifier being operable in response to a trigger ing arrangement to the other end of the second alternatpulse from said triggermeans to transfer energy from said ing current winding of said first saturable inductor, and voltage supply source to said capacitor, whereby a posione end of the control winding of said second saturable tive output signal is produced at said control circuit outinductor being connected in a series opposition arrangeput terminal; ment to the other end of the control winding of said first a second silicon-controlled rectifier having its cathode consaturable inductor whereby a control signal appearing in nected to the negative terminal of said trigger source, its the control windings of said first and second saturable ingate electrode connected to the second output terminal ductors will not be terminals, in the first and second alterof said trigger means and its anode to the first terminal of nating current windings of said first and second saturable said capacitor, said second silicon controlled rectifier inductors; being operable in response to a trigger pulse from said a third saturable inductor having first and second alternattrigger means to transfer energy from said voltage supply ing current windings and a control winding operable in to said capacitor, whereby a negative output signal is response to a control signal to change the inductance produced at said control circuit output terminal; value of said first and second alternating current a third silicon-controlled rectifier having its anode conwindings, the first alternating current winding having one nected to the first terminal of said capacitor and its gate end connected to the fourth terminal of said six terminals, electrode connected to the third output terminal of said one end of said second alternating current winding being trigger means; connected in a series aiding arrangement to the other end a fourth silicon-controlled rectifier having its cathode conof the second alternating current winding of said second nected to the first terminal of said capacitor, its gate elecsaturable inductor, and one end of the control winding of trode connected to the fourth output of said trigger said'third saturable inductor being connected to the fifth means, and its anode connected to the cathode of said terminal of said six terminals; third silicon-controlled rectifier; and

a fourth saturable inductor having first and second alternatan inductor having one end connected to an output terminal ing current windings and a control winding operable in of said control circuit and the other end connected to the response to a control signal to change the inductance common junction of the anode and cathode of the fourth value of said first and second alternating current and third silicon-controlled rectifiers, respectively, said windings, one end of the first alternating current winding third silicon-controlled rectifier being operable in of said fourth saturable inductor being connected in a seresponse to a trigger pulse at its gate electrode to ries aiding arrangement with the other end of the first aldischarge said capacitor, said fourth silicon-controlled ternating current winding of said third saturable inductor 40 rectifier being operable in response to a trigger pulse at its gate electrode to discharge said capacitor.

4. A pulse generation system according to claim 1 wherein said control circuit includes:

a voltage supply source having positive and negative output terminals;

a trigger means having four output terminals, said trigger means being operable to furnish a predetermined sequence of trigger pulses at said output terminals;

a control circuit output terminal;

a capacitor having first and second terminals, said second terminal being connected to said control circuit output terminal;

a first silicon-controlled rectifier having its anode connected to the positive output terminal of said supply source, its gate electrode connected to the first output terminal of said trigger means and its cathode connected to the first terminal of said capacitor, said first siliconcontrolled rectifier being operable in response to a trigger pulse from said trigger means to transfer energy from said saturable inductors, and the series combination of the voltagesupply source to said capacitor, whereby a posisecond alternating current windings of said first and tive output signal is produced at said control circuit outsecond saturable inductors are connected in a series aidput terminal; ing arrangement with the second alternating current a second silicon-control rectifier having its cathode conwindings of said third and fourth saturable inductors nected to the negative terminal of said trigger source, its whereby electric isolation between the series of first altergate electrode connected to the second output terminal nating current windings and the series of second alternatof said trigger means and its anode to the first terminal of ing current windings is provided in the absence of a consaid capacitor, said second silicon-controlled rectifier trol signal in the series-connected control windings. being operable in response to a trigger pulse from said 3. A pulse generation system according to claim 2 wherein trigger means to transfer energy from said voltage supply said control circuit includes: to said capacitor whereby a negative output signal is a voltage supply source having positive and negative output terminals;

a trigger means having four output terminals, said trigger means being operable to furnish a predetermined sequence of trigger pulses at said output terminals;

produced at said control circuit output terminal;

a third silicon controlled rectifier having its anode connected to the first terminal of said capacitor and its gate electrode connected to the third output terminal of said trigger means;

a fourth silicon-controlled rectifier having its cathode connected to the first terminal of said capacitor, its gate electrode connected to the fourth output of said trigger means and its anode connected to the cathode of said third silicon-controlled rectifier; and

an inductor having one end connected to an output terminal of said control circuit and the other end connected to the common junction of the anode and cathode of the fourth and third silicon-controlled rectifiers, respectively, said third silicon-controlled rectifier being operable in response to a trigger pulse at its gate electrode to discharge said capacitor; said fourth silicon-controlled rectifier being operable in response to a trigger pulse at its gate electrode to discharge said capacitor.

5. A pulse generation system according to claim 1 wherein each of said four saturable inductors further includes a bias winding, the bias windings of the first and second saturable inductors being connected in a series opposing arrangement to isolate said bias windings from the series-connected first and second alternating current windings of said first and second saturable inductors, the bias windings of said third and fourth saturable inductors being connected in a series opposing arrangement to isolate said bias windings of said third and fourth saturable inductors from the series-connected first and second alternating current windings of said third and fourth saturable inductors and the series combination of control windings of said first and second saturable inductors being connected in a series opposing arrangement with the series combination of the control windings of said third and fourth saturable inductors, the bias windings being adapted to receive a bias current and to set the quiescent operating points of the saturable inductors and thereby to set the rate of change of inductance of the alternating current windings for a given control signal in the control windings.

6. A variable mutual coupling circuit comprising:

four saturable inductors, each of said saturable inductors having first and second alternating current windings of equal inductance and a control winding, each of said saturable inductors being operative in response to a control signal on said control winding to change the value of inductance of said first and second alternating current windings; and the first alternating current windings of said four saturable inductors being connected in series, the second alternating current windings of said four saturable inductors being connected in series and the control windings of said four saturable inductors being connected in series, said series-connected first alternating current windings being connected in balanced inductance configuration with said series-connected second alternating current windings, said mutual coupling circuit being operable in response to a signal in the series-connected control windings to cause an inductance unbalance between said series-connected first and second alternating current windings whereby mutual coupling exists between said first series-connected alternating current windings and said second alternating current windings.

7. A variable mutual coupling circuit according to claim 6 wherein each of said four saturable inductors further includes a bias winding, the bias windings of the first and second saturable inductors being connected in a series opposing arrangement to isolate said bias windings from the series-connected first and second alternating current windings of said first and second saturable inductors, the bias windings of said third and fourth saturable inductors being connected in a series opposing arrangement to isolate said bias windings of said third and fourth saturable inductors from the series-connected first and second alternating current windings of said third and fourth saturable inductors and the series combination of control windings of said first and second saturable inductors being connected in a series opposing arrangement with the series combination of the control windings of said third and fourth saturable inductors, the bias windings being adapted to receive a bias current and to set the quiescent operating points of the saturable inductors and thereby to set the rate of change of inductance of the alternating current windings for a given control signal in the control windings.

8 A variable mutual coupling circuit comprising:

six terminals;

a first saturable inductor having first and second alternating current windings and a control winding operable in response to a control signal to change the inductance value of said first and second alternating current windings, one end of said first alternating current winding being connected to the first terminal of said six terminals, one end of said second alternating current windings being connected to the second terminal of said six terminals, and one end of said control winding being connected to the third terminal of said six terminals;

a second saturable inductor having first and second alternating current windings and a control winding, operable in response to a control signal to change the inductance value of said first and second alternating current windings, one end of the first alternating current winding of said second saturable inductor being connected in a series aiding arrangement to the other end of the first alternating current winding of said first saturable inductor, one end of said second alternating current winding of said second saturable inductor being connected in a series aiding arrangement to the other end of the second alternating current winding of said first saturable inductor, and one end of the control winding of said second saturable inductor being connected in a series opposition arrangement to the other end of the control winding of said first saturable inductor whereby a control signal appearing in the control windings of said first and second saturable inductor will not be induced in the first and second alternating current windings of said first and second saturable inductors;

a third saturable inductor having first and second alternating current windings and a control winding operable in response to a control signal to change the inductance value of said first and second alternating current windings, the first alternating current winding having one end connected to the fourth terminal of said six tenninals, one end of said second alternating current winding being connected in a series aiding arrangement to the other end of the second alternating current winding of said second saturable inductor, and one of the control windings of said third saturable inductor being connected to the fifth terminal of said six terminals;

a fourth saturable inductor having first and second alternating current windings and a control winding operable in response to a control signal to change the inductance valve of said first and second alternating current windings, one end of the first alternating current winding of said fourth saturable inductor being connected in a series aiding arrangement with the other end of the first alternating current winding of said third saturable inductor and the other end of the first alternating current winding of said fourth saturable inductor being connected in a series opposing arrangement to the other end of the second saturable inductor, one end of the second alternating current winding of said fourth saturable inductor being connected to the other end of the second alternating current winding of said third saturable inductor in a series aiding arrangement, and one end of the control winding of said fourth saturable inductor being connected in series opposition to the other end of the control winding of said third saturable inductor and the other end of the control winding of said fourth saturable inductor being connected in a series-opposing arrangement to the other end of the control winding of said second saturable inductor, whereby having the series combination of the first alternating current windings of said first and second saturable inductors in a series opposing arrangement with the series combination of the first alternating current windings of said third and fourth saturable inductors and having the 10 ries of first alternating current windings and the series of second alternating current windings is maintained in the absence of a control signal in the series connected control windings. 

1. A pulse generation system comprising: an alternating current source including a radio frequency source; storage means having an input terminal and an output terminal and being adapted to store alternating current energy from said alternating current source: a load means including an antenna means; a variable mutual coupling means having first and second input terminals and an output terminal, said first input terminal being connected to the output terminal of said storage means and said output terminal being connected to said load means; and a control circuit having an output terminal connected to said second input terminal of said variable mutual coupling means, said control circuit being operative to supply a control signal of predetermined shape to said variable mutual coupling means, said variable mutual coupling means being operative in response to the control signal from said control circuit to introduce mutual coupling between the first and second input terminals of said variable mutual coupling means whereby the alternating current energy in said storage means is transferred to said load means, said variable mutual coupling circuit including four saturable inductors, each of said saturable inductors having first and second alternating current windings of equal inductance and a control winding, each of said saturable inductors being operative in response to a control signal on its control winding to change the value of inductance of said first and second alternating current windings, the first alternating current windings of said four saturable inductors being connected in series, the second alternating current windings of said four saturable inductors being connected in series and the control windings of said four saturable inductors being connected in series, the series-connected first and second alternating current windings being connected in an inductive balanced configuration with no mutual coupling between said series-connected first alternating current windings and said series-connected control windings, said series-connected first altErnating current windings being connected to said storage means, said series-connected second alternating current windings being connected to said antenna means and said series-connected control windings being connected to said control circuit, said series-connected control windings being operative in response to a signal from said control circuit to change the inductance values of the series-connected first and second alternating current windings whereby an inductance unbalance is created between the seriesconnected first alternating current windings causing the energy stored in said storage means to be transferred to said antenna means.
 2. A pulse generation system according to claim 1 wherein said variable mutual coupling circuit comprises: six terminals; a first saturable inductor having first and second alternating current windings and a control winding operable in response to a control signal to change the inductance value of said first and second alternating current windings, one end of said first alternating current winding being connected to the first terminal of said six terminals, one end of said second alternating current winding being connected to the second terminal of said six terminals, and one end of said control winding being connected to the third terminal of said six terminals; a second saturable inductor having first and second alternating current windings and a control winding, operable in response to a control signal to change the inductance value of said first and second alternating current windings, one end of the first alternating current winding of said second saturable inductor being connected in a series aiding arrangement to the other end of the first alternating current winding of said first saturable inductor, one end of said second alternating current winding of said second saturable inductor being connected in a series aiding arrangement to the other end of the second alternating current winding of said first saturable inductor, and one end of the control winding of said second saturable inductor being connected in a series opposition arrangement to the other end of the control winding of said first saturable inductor whereby a control signal appearing in the control windings of said first and second saturable inductors will not be terminals, in the first and second alternating current windings of said first and second saturable inductors; a third saturable inductor having first and second alternating current windings and a control winding operable in response to a control signal to change the inductance value of said first and second alternating current windings, the first alternating current winding having one end connected to the fourth terminal of said six terminals, one end of said second alternating current winding being connected in a series aiding arrangement to the other end of the second alternating current winding of said second saturable inductor, and one end of the control winding of said third saturable inductor being connected to the fifth terminal of said six terminals; a fourth saturable inductor having first and second alternating current windings and a control winding operable in response to a control signal to change the inductance value of said first and second alternating current windings, one end of the first alternating current winding of said fourth saturable inductor being connected in a series aiding arrangement with the other end of the first alternating current winding of said third saturable inductor and the other end of the first alternating current winding of said fourth saturable inductor being connected in a series-opposing arrangement to the other end of the first winding of the second saturable inductor, one end of the second alternating current winding of said fourth saturable inductor being connected to the other end of the second alternating current winding of said third saturable inductor in a series aiding arrangement, and one end of the control winding of said fourth satUrable inductor being connected in series opposition to the other end of the control winding of said third saturable inductor and the other end of the control winding of said fourth saturable inductor being connected in a series opposing arrangement to the other end of the control winding of said second saturable inductor, thus the series combination of the first alternating current windings of said first and second saturable inductors are connected in series opposing arrangement with the series combination of the first alternating current windings of said third and fourth saturable inductors, and the series combination of the second alternating current windings of said first and second saturable inductors are connected in a series aiding arrangement with the second alternating current windings of said third and fourth saturable inductors whereby electric isolation between the series of first alternating current windings and the series of second alternating current windings is provided in the absence of a control signal in the series-connected control windings.
 3. A pulse generation system according to claim 2 wherein said control circuit includes: a voltage supply source having positive and negative output terminals; a trigger means having four output terminals, said trigger means being operable to furnish a predetermined sequence of trigger pulses at said output terminals; a control circuit output terminal; a capacitor having first and second terminals, said second terminal being connected to said control circuit output terminal; a first silicon-controlled rectifier having its anode connected to the positive output terminal of said supply source, its gate electrode connected to the first output terminal of said trigger means and its cathode connected to the first terminal of said capacitor, said first silicon controlled rectifier being operable in response to a trigger pulse from said trigger means to transfer energy from said voltage supply source to said capacitor, whereby a positive output signal is produced at said control circuit output terminal; a second silicon-controlled rectifier having its cathode connected to the negative terminal of said trigger source, its gate electrode connected to the second output terminal of said trigger means and its anode to the first terminal of said capacitor, said second silicon controlled rectifier being operable in response to a trigger pulse from said trigger means to transfer energy from said voltage supply to said capacitor, whereby a negative output signal is produced at said control circuit output terminal; a third silicon-controlled rectifier having its anode connected to the first terminal of said capacitor and its gate electrode connected to the third output terminal of said trigger means; a fourth silicon-controlled rectifier having its cathode connected to the first terminal of said capacitor, its gate electrode connected to the fourth output of said trigger means, and its anode connected to the cathode of said third silicon-controlled rectifier; and an inductor having one end connected to an output terminal of said control circuit and the other end connected to the common junction of the anode and cathode of the fourth and third silicon-controlled rectifiers, respectively, said third silicon-controlled rectifier being operable in response to a trigger pulse at its gate electrode to discharge said capacitor, said fourth silicon-controlled rectifier being operable in response to a trigger pulse at its gate electrode to discharge said capacitor.
 4. A pulse generation system according to claim 1 wherein said control circuit includes: a voltage supply source having positive and negative output terminals; a trigger means having four output terminals, said trigger means being operable to furnish a predetermined sequence of trigger pulses at said output terminals; a control circuit output terminal; a capacitor having first and second terminals, said Second terminal being connected to said control circuit output terminal; a first silicon-controlled rectifier having its anode connected to the positive output terminal of said supply source, its gate electrode connected to the first output terminal of said trigger means and its cathode connected to the first terminal of said capacitor, said first silicon-controlled rectifier being operable in response to a trigger pulse from said trigger means to transfer energy from said voltage supply source to said capacitor, whereby a positive output signal is produced at said control circuit output terminal; a second silicon-control rectifier having its cathode connected to the negative terminal of said trigger source, its gate electrode connected to the second output terminal of said trigger means and its anode to the first terminal of said capacitor, said second silicon-controlled rectifier being operable in response to a trigger pulse from said trigger means to transfer energy from said voltage supply to said capacitor whereby a negative output signal is produced at said control circuit output terminal; a third silicon controlled rectifier having its anode connected to the first terminal of said capacitor and its gate electrode connected to the third output terminal of said trigger means; a fourth silicon-controlled rectifier having its cathode connected to the first terminal of said capacitor, its gate electrode connected to the fourth output of said trigger means and its anode connected to the cathode of said third silicon-controlled rectifier; and an inductor having one end connected to an output terminal of said control circuit and the other end connected to the common junction of the anode and cathode of the fourth and third silicon-controlled rectifiers, respectively, said third silicon-controlled rectifier being operable in response to a trigger pulse at its gate electrode to discharge said capacitor; said fourth silicon-controlled rectifier being operable in response to a trigger pulse at its gate electrode to discharge said capacitor.
 5. A pulse generation system according to claim 1 wherein each of said four saturable inductors further includes a bias winding, the bias windings of the first and second saturable inductors being connected in a series opposing arrangement to isolate said bias windings from the series-connected first and second alternating current windings of said first and second saturable inductors, the bias windings of said third and fourth saturable inductors being connected in a series opposing arrangement to isolate said bias windings of said third and fourth saturable inductors from the series-connected first and second alternating current windings of said third and fourth saturable inductors and the series combination of control windings of said first and second saturable inductors being connected in a series opposing arrangement with the series combination of the control windings of said third and fourth saturable inductors, the bias windings being adapted to receive a bias current and to set the quiescent operating points of the saturable inductors and thereby to set the rate of change of inductance of the alternating current windings for a given control signal in the control windings.
 6. A variable mutual coupling circuit comprising: four saturable inductors, each of said saturable inductors having first and second alternating current windings of equal inductance and a control winding, each of said saturable inductors being operative in response to a control signal on said control winding to change the value of inductance of said first and second alternating current windings; and the first alternating current windings of said four saturable inductors being connected in series, the second alternating current windings of said four saturable inductors being connected in series and the control windings of said four saturable inductors being connected in series, said series-connected first alternating current windiNgs being connected in balanced inductance configuration with said series-connected second alternating current windings, said mutual coupling circuit being operable in response to a signal in the series-connected control windings to cause an inductance unbalance between said series-connected first and second alternating current windings whereby mutual coupling exists between said first series-connected alternating current windings and said second alternating current windings.
 7. A variable mutual coupling circuit according to claim 6 wherein each of said four saturable inductors further includes a bias winding, the bias windings of the first and second saturable inductors being connected in a series opposing arrangement to isolate said bias windings from the series-connected first and second alternating current windings of said first and second saturable inductors, the bias windings of said third and fourth saturable inductors being connected in a series opposing arrangement to isolate said bias windings of said third and fourth saturable inductors from the series-connected first and second alternating current windings of said third and fourth saturable inductors and the series combination of control windings of said first and second saturable inductors being connected in a series opposing arrangement with the series combination of the control windings of said third and fourth saturable inductors, the bias windings being adapted to receive a bias current and to set the quiescent operating points of the saturable inductors and thereby to set the rate of change of inductance of the alternating current windings for a given control signal in the control windings. 8 A variable mutual coupling circuit comprising: six terminals; a first saturable inductor having first and second alternating current windings and a control winding operable in response to a control signal to change the inductance value of said first and second alternating current windings, one end of said first alternating current winding being connected to the first terminal of said six terminals, one end of said second alternating current windings being connected to the second terminal of said six terminals, and one end of said control winding being connected to the third terminal of said six terminals; a second saturable inductor having first and second alternating current windings and a control winding, operable in response to a control signal to change the inductance value of said first and second alternating current windings, one end of the first alternating current winding of said second saturable inductor being connected in a series aiding arrangement to the other end of the first alternating current winding of said first saturable inductor, one end of said second alternating current winding of said second saturable inductor being connected in a series aiding arrangement to the other end of the second alternating current winding of said first saturable inductor, and one end of the control winding of said second saturable inductor being connected in a series opposition arrangement to the other end of the control winding of said first saturable inductor whereby a control signal appearing in the control windings of said first and second saturable inductor will not be induced in the first and second alternating current windings of said first and second saturable inductors; a third saturable inductor having first and second alternating current windings and a control winding operable in response to a control signal to change the inductance value of said first and second alternating current windings, the first alternating current winding having one end connected to the fourth terminal of said six terminals, one end of said second alternating current winding being connected in a series aiding arrangement to the other end of the second alternating current winding of said second saturable inductor, and one of the control windings of said third saturable inductor being connected to the fifth teRminal of said six terminals; a fourth saturable inductor having first and second alternating current windings and a control winding operable in response to a control signal to change the inductance valve of said first and second alternating current windings, one end of the first alternating current winding of said fourth saturable inductor being connected in a series aiding arrangement with the other end of the first alternating current winding of said third saturable inductor and the other end of the first alternating current winding of said fourth saturable inductor being connected in a series opposing arrangement to the other end of the second saturable inductor, one end of the second alternating current winding of said fourth saturable inductor being connected to the other end of the second alternating current winding of said third saturable inductor in a series aiding arrangement, and one end of the control winding of said fourth saturable inductor being connected in series opposition to the other end of the control winding of said third saturable inductor and the other end of the control winding of said fourth saturable inductor being connected in a series-opposing arrangement to the other end of the control winding of said second saturable inductor, whereby having the series combination of the first alternating current windings of said first and second saturable inductors in a series opposing arrangement with the series combination of the first alternating current windings of said third and fourth saturable inductors and having the series combination of the second alternating current windings of said first and second saturable inductors connected in a series aiding arrangement with the second alternating current windings of said third and fourth saturable inductors whereby electric isolation between the series of first alternating current windings and the series of second alternating current windings is maintained in the absence of a control signal in the series connected control windings. 